Summary of the Invention
This invention relates to a fuel pumping apparatus for supplying fuel to an internal combustion engine and of the kind comprising a rotary distributor member journalled in a pump body and arranged to be driven in use in timed relationship with the associated engine, a pumping plunger mounted in a bore in the distributor member, cam means for imparting inward movement to the plunger, a delivery passage in the distributor member in communication with the bore, the delivery passage registering in turn with a plurality of outlets in the pump body during successive inward movements of the pumping plunger, a spill valve operable to allow fuel to spill from the bore, a fluid pressure operable piston for actuating the spill valve, an auxiliary plunger carried by the distributor member, the auxiliary plunger being operated at the same time as the pumping plunger, and a control valve including a fluid pressure operable component movable by the fluid delivered by said auxiliary plunger, said control valve controlling the application of fluid under pressure to said piston.
The object of the present invention is to provide an apparatus of the kind specified in a simple and convenient form.
According to the invention the control valve at a predetermined position in the movement of said component opens to apply the fluid under pressure delivered by said auxiliary plunger to said piston.
According to a further feature of the invention said control valve comprises an outer fixed member defining a cylindrical bore, an inner member in the form of an angularly adjustable rod, said component being of annular form and being slidably located between the inner and outer members, said annular component at one end being exposed to the pressure of fluid delivered by said auxiliary plunger, resilient means for opposing the movement of the component and valve means defined by the component and the rod whereby after a predetermined axial movement of the component against the action of the resilient means and depending on the relative angular position of the component and the rod, the valve means opens to allow the fluid pressure developed by the auxiliary plunger to act on said piston.
According to a still further feature of the invention the rod is coupled to a governor mechanism and the component is angularly adjustable in accordance with an engine operating parameter.